States of matter: Basics

The title of the Project: States of matter: Basics

This virtual laboratory is intended for use in chemistry classes on the following topics:

  • 7th grade. Chapter II. “Changes in the state of matter”.


  • to explore the characteristics of solids, liquids, and gases
  • to understand how temperature and pressure affects the state of matter
  • to introduce students to the concept of phase changes

Practical part

This simulation helps students explore solids, liquids, and gases.

  1. Launch the simulation. You’ll see two screens: “States”and “Phase changes”. Look at the “States” screen first.

The “States” screen

Here, you can investigate the characteristics of the three states of matter.

  1. The simulation shows a container of particles. Choose a molecule to investigate from the list.

3. Play with the screen. Describe the characteristics (shape, volume, particle motion) of each state (solid, liquid, gas) for the chosen molecule. Use the buttons to display the solid, liquid, or gas form.

4. See what happens when heat energy is added or removed from the container using the slider.

5. Track temperature changes with the thermometer. Change units from Kelvin to Celsius using the dropdown menu.

6. Once you’ve explored all three states, reset the simulation and display water molecules.

7. Pause the simulation to compare the structure of water molecules in solid, liquid, and gas states.

The “Phase changes” screen

Now, switch to the “Phase Changes” screen to see how temperature and pressure affect the behavior of particles.

  1. This workspace is similar to the previous one, allowing you to investigate the same atoms or molecules. However, this screen has several additional features, including the ability to add additional particles into the container using the pump or to measure the pressure in the container.

9. Choose a substance, like Argon. Use the tools to cause a phase change in this substance.

10. Besides adding/removing heat, you can also move the container lid to cause a phase change. 

11. Open the “Phase Diagram” panel to track the current state of matter represented by the particles.

12. Note that increasing pressure to the maximum makes the lid fly off. Use the “Return Lid” button to put the lid back on and particles back in the container.

  1. Discuss with your partner and answer the questions to wrap-up the work. Draw conclusions.
  • How does the arrangement of particles differ between solids, liquids, and gases? 
  • How does temperature affect particle movement? 
  • What happens to the particles when a solid melts (becomes a liquid)? 
  • What happens to the particles when a liquid boils (becomes a gas)? 


Students explored the world of states of matter using this simulation. Now they can describe the properties of solids, liquids, and gases. Students can also explain how temperature and pressure can change the state of matter.